Conventional procedures for using textured yarns include pin twisting and friction twisting. In such procedures, problems may result including broken filaments. Further, in such procedures, there is not as much positive twist control as desired, the fiber finish often leaves something to be desired, the bulk of the textured yarn may be less than desirable, and there is a capacity for only applying a limited number of turns per inch. Also there are some fine denier filaments and weaker thermoplastic filaments (e.g., Arnel) which cannot be processed thereby.
According to the present invention, a new texturizing process is provided, utilizing particular apparatus, which overcomes a number of the problems inherent in prior art texturizing procedures. According to the present invention, better positive twist control is provided than is possible in the prior art conventional procedures, and the yarn is handled in a more gentle manner. This allows textured bulk, stretch-type yarn to be produced even from fine denier filaments and from weaker thermoplastic filaments, that could not be processed utilizing conventional techniques.
According to one aspect of the present invention, a yarn texturizing apparatus is provided. The conventional components of the apparatus include a feed means, a heater block, and output means. According to the invention, disposed between the heater block and the output means is a spindle comprising a perforated cylinder having a generally axially through-extending passageway, means for mounting the cylinder for rotation about an axis coincident with the passageway, means for rotating the cylinder, a source of vacuum, and means for connecting the vacuum to the exterior of the cylinder. The heater is generally in-line with the cylinder passageway, and the cylinder passageway may have a number of configurations and cooperative features with perforations, such as a V-shaped offset portion. The mounting means preferably comprises a mounting tube having interior dimensions significantly greater than the exterior dimensions of the perforated cylinder, the tube connected through a passageway to the vaccum, and the bearing means being provided between the tube and the cylinder. The entering portion of the cylinder passageway is preferably circular in cross-section and has a diameter approximately twice as great as the diameter of a single filament yarn (or composite diameter of a multi-filament yarn) fed into it, while the exit portion of the passageway from the cylinder has a diameter of about 1.5 times the diameter of the exiting yarn.
According to another aspect of the present invention, a method of texturizing a yarn is provided, which method utilizes a heater block, a spindle including a perforated cylinder with a generally axially through-extending passageway, and a source of vacuum. The method comprises the following steps: (a) Feeding yarn to be texturized through the heater block, in operative contact therewith, to the perforated cylinder generally axially extending passageway. (b) Imparting twist to the yarn in the cylinder, which twist is backed up to the heater block wherein the twist is set in a semi-permanent, false twist configuration; and (c) Removing the yarn from the cylinder at which time the twist relieves itself and a textured, bulk, stretch-type yarn is produced. Step (b) is practiced by rotating the cylinder while applying vacuum to the exterior thereof so that the yarn is held by the force of the vacuum against the inner wall of the cylinder, and the rotation of the cylinder imparts twist to the yarn. The rotation typically is at a speed of several hundred thousand rpm, while the applied vacuum is in the range of about 8-12 inches of mercury.
Also according to the present invention, it is possible to produce a textured, bulk, stretch-type yarn from fine denier filaments and/or weak thermoplastic filaments, such filaments being so fine and/or weak that they normally are not capable of being texturized using conventional pin twisting and friction twisting processes.
It is the primary object of the present invention to provide for the production of textured, bulk, stretch-type yarn, planned positive twist control, and the application of a gentle action to the yarn during production. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.